Coating Defects Flashcards
Inspectors should consult with the manufacturer’s ___ ____ about coating failures whenever possible.
Tech Rep
Nondrying Film (Failure to cure) is a common problem on many projects, frequently caused by not adding the 1___ to the ___, adding the 2___ ___ or not adding the 3___ ___ of ___.
It is vitally important to the success of the project that the inspector observe during mixing.
- Not adding cure to the base.
- Adding the wrong cure.
- Not adding the correct amount of cure.
Nondrying cure may also be caused by an issue with the coating itself. A quick check with the manufacturer using the ___ ___ might have a quick answer.
Batch Number.
Nondrying/failure to cure defect causes could be:
- Environmental conditions: ___ ___, ___ or ___ conditions
- ___ or ___ thinner.
- ___ in some generic thinners can react with the cure.
- Not adding ___ to the base. Or adding the ___ ___ or ___ ___.
- Too hot, cold or humid conditions.
- Wrong/contaminated thinner.
- Moisture in some generic thinners can react with the cure.
- Not adding cure to the base. Or adding the wrong types or wrong amounts.
(Based upon Photo) A non cured coating seems to look like a tar, similar to tobacco tar with about the same consistency.
Note.
(Based upon Photo) Amine blush looks like dried milk on the surface.
Note.
If cured during conditions of cool ambient temps, dropping temps, or high humidity ___ ___ ___ ___ coatings can develop a surface oiliness or exudate. Commonly referred to as Amine Blush or Amine Sweating.
Amine Cured Epoxy Resin Coatings.
If cured during conditions of cool ambient temps, dropping temps, or high humidity amine cured epoxy resin coatings can develop a ___ ___ or ___. Commonly referred to as Amine Blush or Amine Sweating.
Surface oiliness or exudate.
Exudate is a ___ ___.
Secreted Substance.
Amine Blush/Sweating is caused by the absorption of ___ ___ and ___ into the coating film and it’s reaction with amine curing.
Carbon dioxide and water.
Causes of Amine Blush/Sweating are:
- Too ___ or ___ temps during curing.
- High ___ during curing.
- A drop in ___ during coating.
- Too hot or cold temps during curing.
- High humidity during curing.
- A drop in temp during coating.
Some of the problems with amine blush/sweating can be:
- Surface ___ or ___.
- Incomplete ___.
- Poor ___.
- Poor ___ on ___ ___.
- Coating ___ over time.
- Poor ___ retention.
- Surface tackiness or greasiness.
- Incomplete cure.
- Poor adhesion.
- Poor adhesion on over coating.
- Coating discoloration over time.
- Poor gloss retention.
The best method to fix amine blush is to 1?
- If amine blush does occur the CI should consult with the ___ ___ and the ___ ___ prior to making any recommendation regarding the attempt to repair/over coat it.
- Avoid it by adhering to strict environmental controls. (This is not a fix, you morons. This is prevention.)
- Coating manufacturer and the project engineer.
There are a number of kits on the market to detect amine blush.
Just a note.
If the kits can detect it, doesn’t that mean it’s already happening and the kit is just letting you know a short period of time before it’s visible? What good is that?
Runs, sags, curtains or wrinkles may be caused or worsened by:
- Applying the coating ___ ___.
- Using too much, or the wrong, ___.
- Surface is ___ ___ to apply the coating.
- Applying the coating at the end of its ___ ___.
- Wrong thixotrope used in ___.
- Improper ___ ___.
- Applying the coating too thickly.
- Using too much, or the wrong, thinner.
- Surface is too hot to apply the coating.
- Applying the coating at the end of its pot life.
- Wrong thixotrope used in manufacturing.
- Improper spray technique.
The first step to addressing a run or drip is to see if the applicator can fix it right away by 1___ or ___ the coating with a 2. ___ or ___.
If the run or drip is already hard, report the issue to the owner.
- Lifting or Spreading.
2. Brush or roller.
In some cases a run or sag is acceptable. Otherwise, ensure the crew ___ it ___ and ___ the new material at the ___ ___, based on the specification and manufacturers’ recommendation for repairs.
Sands it down and applies the new material at the correct thickness,
(According to photo) runs looks like half melted coating, or a puddle of coating.
Just a note.
Discontinuities, skips, holidays and missed areas:
These defect are 1___ ___ of the substrate or previous coating caused by:
- Poor ___ ___,
- Lack of a ___ ___.
- Lack of ___
- Poor ___
- Exposed Areas
- Poor application technique.
- Lack of a stripe coat.
- Lack of Inspection.
- Poor Inspection.
Discontinuities, skips, holidays and missed areas:
Base the repair on the 1___. If there is no recommended repair procedures, then leave the method up to the 2____ ___.
- Ensure the ___ gives ___ before making the repair.
- Specification.
- Manufacturers recommendations.
- Owners gives approval.
Chalking is a powdery, friable layer on the surface of a coating normally cause by 1___ to ___ ___.
It can also be due to exposure to other forms of 2 ____ including ___ ___.
- Exposure to UV Light.
2. Radiation. Including nuclear radiation.
The UV Light or radiation break down the bond 1___ ___ in the coating film. It is most common in 2___ films but can be seen in almost all coatings left to exposure to causative conditions.
- Between Molecules.
2. Epoxy
To overcoat Chalking:
- Remove the powdery later by ___ or ___ ___ to a point acceptable to the project owner.
Sanding or pressure washing.
ASTM D4214-07 is the?
Standard test methods for evaluating the degree of chalking of exterior paint films.
(According to Photo) Cratering is pretty. It looks like small indentations with raised edges. Similar to what you would expect on the surfae of the moon.
Just a note.
Cratering is the formation of a small bowl-shaped depression in the coating caused by ___ trapped in the coating. It can also be caused by 2___ ___ __.
Air.
- Improper mixing procedures.
Cratering is common in coatings that are ___ or ___ ___ by an inexperienced applicator.
Roller or Brush applied.
Air in the coating, sometimes caused by Brush/Roller application or improper mixing procedures can cause?
Cratering.
Cratering is also known as?
Vacuoles and pinholing.
Exposure to UV or other radiation sources can cause a coating to?
Chalking
These are caused by air trapped in a coating during mixing which creates a foam or bubbly surface on the liquid coating.
Air Voids
While initially invisible, Air voids generally lead to a coating failure in the?
Near future.
Air voids are pockets of air trapped inside the coating film during ___ and creates a foam or bubbly surface n the coating.
Mixing.
When a mixer is run too fast air can become trapped in the coating causing?
Air Voids.
(According to Photo) Air voids look just like foam.
Just a note.
Pinholes are very small holes in a coating caused by painting over an 1___ ___ ___ or ___ ___ ___.
- ___ or ___ escaping through a porous film cause these tiny holes.
- Zinc coatings ___ ___ so quickly that these holes will not fill back in.
- Inorganic Zinc Coating or sprayed metal coatings.
- Air or solven.
- Sets up.
Pinholes are easy to avoid by simply using a ___ ___ followed by a ___ ___.
Mist coat followed by a full coat.
The repairs for 1____, ___, and ___ are very difficult since the hole generally reforms in any coating applied over them. The only sure fix is 2___ ___ to ___ ___.
- Pinholing, Cratering, and Vacuoles.
2. Sanding down to bare metal.
The repairs for 1____, ___, and ___ are very difficult since the hole generally reforms in any coating applied over them. The only sure fix is 2___ ___ to ___ ___.
- Pinholing, Cratering, and Vacuoles.
2. Sanding down to bare metal.